SUMMARY: The 2020 Gordon Research Conference (GRC) on Ligand Recognition and Molecular Gating will be held from March 15th-20th at the Renaissance Tuscany Il Ciocco Resort, Italy. The GRC will be preceded by the related Gordon Research Seminar (GRS), which is organized by and for young scientists (March 14th-15th). The topic of this GRC/GRS combination is unique, as it addresses the molecular mechanisms of three important classes of membrane proteins: ion channels, active transporters, and G-protein coupled receptors (GPCRs). These proteins are central to human physiology and their dysfunction leads to a large number of neuromuscular, endocrine and metabolic diseases. These proteins are major therapeutic targets; more than 50% of current drugs on the market target them. Therefore, elucidating their molecular mechanisms is essential to enable new opportunities for intervention, which ultimately will lead to improvement of human health. The central focus of this GRC/GRS is on the molecular mechanisms underlying ligand recognition and binding, ligand-induced conformational changes, solute transport, regulation of function, and signal transmission. Current focus is on elucidating the structures of these proteins and on how the structural data illuminates the mechanisms and physiological roles of these proteins. Our understanding of membrane protein function is undergoing a major leap forward, fueled by multiple technological breakthroughs, the most important of which is the revolution in electron cryo- microscopy that led to the determination of several medically important structures of human transporters, channels and signaling complexes, such as Na+ channels, multidrug ABC transporters and GPCR/G- protein complexes. Progress has also been made in understanding fundamental processes that are key to the function of these proteins, such as gating mechanisms of major channels, dynamic rearrangements and the formation of different signaling complexes. Efforts to identify the function of uncharacterized membrane protein families are also underway to understand their function in human physiology and disease. This GRC is unique as it brings together scientists who work on these three different classes of membrane proteins and are located on different continents, and thus do not meet regularly. They will benefit tremendously from these interactions as these membrane proteins share common mechanistic principles and can be studied by a vast array of techniques, many of which will be represented in this conference. The program will have around 40 speakers, a mix of well-established leaders in the field, young investigators, postdocs and graduate students. Nine speaker sessions and several poster sessions will address the major properties of transporters, ion channels, and GPCRs. The GRC/GRS on Ligand Recognition and Molecular Gating will provide a platform for the presentation and discussion of latest research results and for the establishment of new collaborations.